JPH07282751A - Fluorescent display tube - Google Patents

Abstract

PURPOSE:To provide a multicolor display with high brightness and long service life without using a sulfide phosphor and to provide it with high quality and high reliability without causing discontinuity of positive electrode layers and a wiring layer, the degradation of filter layers and the degradation of phosphor layers or the like. CONSTITUTION:Positive electrode layers 2a and 2b and insulating layers 3 are formed in prescribed positions on a glass substrate 1, and a blue filter layer 6b to which electric conductivity is applied by covering a surface with an ITO and which is composed of blue pigment is formed on the positive electrode layer 2a, and a yellow filter layer 6y to which electric conductivity is applied by covering a surface with an ITO and which is composed of yellow pigment is formed on the positive electrode layer 2b. After phosphor layers 4A composed of a ZnO:Zn phosphor are formed on these filter layers 6b and 6y, they are baked in the atmosphere, and are formed by buring an organic binder contained in the filter layers 6b and 6y and the phosphor layers 4A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube for displaying by utilizing light emission of a phosphor excited by a low-speed electron beam, and in particular, a structure for observing a light emitting portion through a transparent anode substrate. The present invention relates to a so-called reverse view type fluorescent display tube.

[0002]

2. Description of the Related Art Conventionally, two structures have been proposed for obtaining different emission colors in a fluorescent display tube having a structure in which a light emitting portion is observed through a transparent anode substrate. First, the first
As a structure of Al, ITO (indium, etc.) deposited by a sputtering method or the like on the glass substrate 1 as a light-transmissive anode as shown in the enlarged sectional view of the main part in FIG.
Thin oxide film (tin oxide: In ₂ O ₃ + SnO ₂ mixed crystal) or the like is used to form a transparent anode layer 2 and a wiring layer (not shown) by a photoetching method, and then an insulating paste containing low melting point glass as a main component is screened. It is applied by a printing method and baked to form the insulating layer 3.

Thereafter, a phosphor paste is applied onto the anode layer 2 by a screen printing method to form the phosphor layers 4a and 4b by adhesion. Here, different emission colors can be obtained by changing the type of phosphor applied. For example, ZnO: Zn (emission color: blue-green) is added to the phosphor layer 4a, and phosphor layer 4b is used.
By forming ZnCdS: Ag + In ₂ O ₃ (emission color: red), respectively, two-color display of blue green and red can be obtained.

As a second structure, color filter layers 5a and 5b having different absorption characteristics are formed on the translucent glass substrate 1 as shown in the enlarged sectional view of the main part of FIG. The color filter layers 5a and 5b are formed by applying a paste containing a pigment and low melting point glass as a main component or a paste such as copper stain (pigment containing copper) by a printing method and firing the paste. Next, the above-mentioned first
After forming the anode layer 2 and the insulating layer 3 in the same manner as the structure of
ZnO: Zn having high efficiency and long life for low-speed electron beam excitation
The phosphor layer 4 is formed of (luminescent color: blue-green).

In such a structure, when the color filter layers 5a and 5b are blue and yellow filter layers, respectively, the emission of the ZnO: Zn phosphor layer 4 having a broad emission spectrum is caused by these filter layers 5a and 5b. , Are converted into blue and yellow, respectively, and a two-color display is obtained. Also, three or more colors can be obtained in the same manner.

[0006]

However, the above-mentioned first structure and second structure have the following problems, respectively. (First Structure) Phosphor layers 4a, 4 for performing multicolor display
b is (ZnCdS: Ag + In ₂ O ₃ ) or (ZnCdS: Ag + In ₂ O ₃ ).
When a sulfide-based phosphor such as S: Zn + In ₂ O ₃ ) is used, the surface of the sulfide-based phosphor is decomposed by a low-speed electron beam, the cathode is damaged, and the life is shortened. .

(Second Structure) After the color filter layers 5a and 5b are formed on the glass substrate 1, a thin film of Al, ITO or the like deposited by a sputtering method or the like is photoetched to form the anode layer 2 and the wiring layer. When forming,
Since the filter layer containing the pigment and the low melting point glass as main components has a thickness of several μm or more, when photo-etching a thin film of Al, ITO, or the like, disconnection is likely to occur due to these steps. Further, the low melting point glass contained in the color filter layers 5a and 5b is attacked by the etching solution, and the color filter layers 5a and 5b become turbid. Also,
The stain method requires a cleaning step to remove the residue after firing the paste, and the A
Ions such as u, Ag, and Cu diffuse into the phosphor layer 4 in the heating process of the fluorescent display tube, and deteriorate the light emission characteristics.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to obtain a multicolor display with high brightness and long life without using a sulfide-based phosphor. The present invention provides a fluorescent display tube.
Another object of the present invention is to provide a fluorescent display tube of high quality and high reliability, which is free from disconnection of the anode layer and wiring layer, deterioration of the filter layer, deterioration of the phosphor layer, and the like.

[0009]

In order to achieve such an object, a fluorescent display tube according to the present invention has a conductive color filter layer interposed between an anode substrate and a phosphor layer.

[0010]

The conductive color filter layer of the present invention enables multicolor display without using a sulfide-based phosphor. Further, the conductive color filter layer in the present invention also has a function as an anode layer.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. (Embodiment 1) FIG. 1 is a cross-sectional view of an essential part showing the construction of an embodiment of a fluorescent display tube according to the present invention.
The same reference numerals are given to the same portions as. In the figure,
On the translucent glass substrate 1, I is formed at the site where the phosphor layer is formed.
An anode layer 2a, an anode layer 2b, and a wiring layer (not shown) are formed by a photo-etching method of the TO thin film, and an insulating layer 3 is further formed on the peripheral portion thereof.

On one of the anode layers 2a, a paste composed of a blue pigment such as cobalt aluminate whose surface is coated with ITO to give conductivity by a sputtering method and a vehicle is applied by a printing method. Then, a blue filter layer 6b is formed by drying, and similarly, on the other anode layer 2b, a paste composed of a yellow pigment such as titanium yellow and a vehicle whose surface is coated with ITO to impart conductivity is formed. The yellow filter layer 6y is formed by applying by a printing method and drying.

On the blue filter layer 6b and the yellow filter layer 6y, a paste composed of, for example, ZnO: Zn phosphor and a vehicle as an oxide-based phosphor is applied by a printing method and dried to cause fluorescence. The body layer 4A is formed. Further, the glass substrate 1 on which the blue filter layer 6b, the yellow filter layer 6y and the phosphor layer 4A are formed is fired at about 500 to 550 ° C. in the air to obtain the blue filter layer 6b, the yellow filter layer 6y and After the organic binder contained in the phosphor layer 4 is burned and removed, it is made into a bulb through a normal manufacturing process of a fluorescent display tube to emit blue light and yellow light. 2
A color display fluorescent display tube is obtained.

(Embodiment 2) FIG. 2 is a cross-sectional view of an essential part showing a structure of a fluorescent display tube according to another embodiment of the present invention.
The same parts as those in FIGS. 3 and 4 are designated by the same reference numerals.
In the figure, a wiring layer (not shown) is formed on the translucent glass substrate 1 by a photo-etching method of an Al thin film, and then an insulating layer 3 having an opening portion is formed at a portion where a phosphor layer is formed. .

Further, in the opening of the insulating layer 3 formed on the glass substrate 1, for example, a red pigment such as red iron oxide and a green pigment such as chromium oxide are used as conductive materials, and powders of In ₂ O ₃ are used. A red paste layer 7r and a green filter layer 7g are respectively formed by applying a printing paste in which a body and a vehicle are mixed by a printing method, and an oxide-based phosphor is formed on the red filter layer 7r and the green filter layer 7g. For example, a phosphor layer 4A is formed by applying a paste including a ZnO: Zn phosphor and a vehicle by a printing method and drying the paste.

In this case, the filter layer 7r and the filter layer 7g contain In ₂ O ₃ powder as a conductive substance and also have a function as an anode, and are electrically connected to a wiring layer (not shown). There is. In addition, the glass substrate 1 on which the red filter layer 7r, the green filter layer 7g and the phosphor layer 4A are formed is 500 in the atmosphere.
After being burned at about 550 ° C. to burn and remove the organic binder contained in the red filter layer 7r, the green filter layer 7g and the phosphor layer 4A, the bulb is subjected to a normal fluorescent display tube manufacturing process. As a result, a two-color fluorescent display tube that emits red light and green light can be obtained.

In the above-mentioned embodiments, the case where the surface of the pigment is coated by sputtering of ITO and the case where the pigment is mixed with In ₂ O ₃ powder have been described, but the present invention is not limited to these. Alternatively, the same effect as described above can be obtained by using a pigment whose surface is coated with another conductive material such as SnO ₂ using an electron beam evaporation method, a plating method, or the like.

In the above-mentioned embodiment, the case where an oxide type phosphor such as ZnO: Zn phosphor is used as the phosphor has been described, but the present invention is not limited to this. ₂ O ₃ system phosphor or ZnSiO
The same effect as described above can be obtained by using a _4- system phosphor.

[0019]

As described above, according to the present invention,
By interposing a conductive color filter layer between the translucent anode substrate and the phosphor layer, multicolor display can be performed without using a sulfide-based phosphor, so that the emission characteristics of the phosphor layer can be improved. It has an extremely excellent effect that a fluorescent display tube having high brightness and long life can be obtained without deterioration.

Further, since the filter layer is formed after forming the anode layer and the wiring layer on the translucent anode substrate, disconnection of the anode layer and the wiring layer in the conventional structure, deterioration of the filter layer due to photoetching, and filter layer The deterioration of the phosphor due to the diffusion of ions from the solution is eliminated, and the washing step after the filter layer formation is not required, so that it is possible to obtain a fluorescent display tube of high quality and high reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part showing a substrate structure according to an embodiment of a fluorescent display tube according to the present invention.

FIG. 2 is a cross-sectional view of an essential part showing a substrate structure according to another embodiment of a fluorescent display tube according to the present invention.

FIG. 3 is a cross-sectional view of an essential part showing a substrate structure of a conventional fluorescent display tube.

FIG. 4 is a cross-sectional view of an essential part showing a substrate structure of a conventional fluorescent display tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2a ... Anode layer, 2b ... Anode layer, 3 ... Insulating layer, 4A ... Phosphor layer, 6b ... Blue filter layer, 6y
… Yellow filter layer, 7r… Red color filter, 7g
… Green color filter.

Claims (2)

[Claims] 1. A fluorescent display tube for observing a phosphor layer through a translucent anode substrate, characterized in that a conductive color filter layer is interposed between the anode substrate and the phosphor layer. Fluorescent display tube. 2. The fluorescent display tube according to claim 1, wherein the color filter layer is mainly composed of a pigment having conductivity.